Notes, summaries, assignments, exams, and exercises for Computer science for Primary education

UrarenKalitatea Pascal Source Code

The following is a complete Pascal program designed to manage and calculate water quality measurements and indices.

PROGRAM UrarenKalitatea ;

USES
  Crt, SysUtils ;

CONST
  MAX_NEURKETAK = 1000 ;

TYPE
  tsKateLabur = STRING [10] ;
  tsKateLuze = STRING [150] ;
  tarOinarrizkoParametroak = ARRAY [1..9] OF Real ;
  trdNeurketa = RECORD
    sBehatokia,
    sData: tsKateLabur ;
    rKIO: Real ;
    iKI: Integer ;
    arParametroak : tarOinarrizkoParametroak ;
  END ;
  tardNeurketenZerrenda = ARRAY [1..MAX_NEURKETAK] OF trdNeurketa ;
  tfrdNeurketenFitxategia = FILE OF trdNeurketa ;

FUNCTION fncAukeraIrakurri : Char ;
VAR
  cAukera : Char ;
BEGIN
  Writeln('1. Neurketen fitxategiaren edukia erakutsi') ;
  Writeln(

1) What is C++? Advantages of C++

C++ is an object-oriented programming language developed by Bjarne Stroustrup. It is an extension of the C language.

Advantages:

• Supports Object-Oriented Programming.
• Code reuse using inheritance.
• Fast execution.
• Data security through encapsulation.
• Portable language.
• Supports function and operator overloading.

2) Difference Between Procedural and Object-Oriented Programming

3) Six Advantages of OOP

1. Data hiding provides security.
2. Code reusability using inheritance.
3. Easy program maintenance.
4. Reduces program complexity.
5. Easy debugging.

Backup

Important directories: /etc, /home, /var, /usr, /local

Package and compress with tar. Files: home.tar

# tar -cvf home.tar /home

Compression:

# gzip -r /home/* (recursive compression)

Decompression:

# gunzip -r /home/* (recursive decompression)

Cryptography

In cryptography, digital signatures are a digital information authentication method, known as signature.

The art of cryptanalysis is the study of attempts to break ciphertext.

Key + algorithm + message = ciphertext

CID + Authentication + Irretrievability

Encryption: C = Ek(M). Decryption: M = Dk(C)

Steganography: secret communication by hiding the existence of the message.

Steganalysis: detection of steganographic content.

Examples of cryptographic protocols: SSL, SSH, IPSec, WEP, WPA

Symmetric algorithms:...

Client Facilities

Client Facilities: Performance, ensure integrity, updates, risk confidential. Static pages, forms, active content, plugins, stand-alone applications.

XML

XML (Extensible Markup Language): Preferred form for B2B and internal documents with legal effect. Key benefits: non-proprietary, platform independent, HTTP compatibility, international support, extensible, self-defining, common tools, and transformation. Complementary techniques: UDDI (Universal Description, Discovery, and Integration), WSDL (Web Services Description Language) – web service design. Signatures have legal effect.

Components

Components: Good because turn-key systems tend to be too large and inflexible. Advantages: higher quality and design, maintenance shared,...

C Example 1: Writing Structured Data to a File

This program demonstrates appending structured date data (assuming struct fecha is defined elsewhere) to a file named Dades.txt. It includes basic file opening and error checking.

#include <stdio.h>
#include <stdlib.h>

int main() 
{
    int temp = 1;
    int auxiliar = 0;
    int i = 0;
    FILE *v1;
    
    v1 = fopen("Dades.txt", "a");
    
    // Note: Variables 'origen' and 'destino' are undefined in this snippet.
    if (origen == NULL || destino == NULL) {
        printf("Problemas con los ficheros.\n");
        exit(1);
    }
    
    printf("Inserte el día, mes y año. El programa finalizará marcando 0 en el día:\n\n");
    
    while (temp != 0) {
        printf("Día:\

1. C++ Pointer Declaration and Initialization

Ans:

#include <iostream>
using namespace std;

int main() {
    int num = 10;
    int *ptr = &num;
    cout << "Value of num: " << num << endl;
    cout << "Address of num: " << &num << endl;
    cout << "Pointer ptr stores: " << ptr << endl;
    cout << "Value pointed by ptr: " << *ptr << endl;
    return 0;
}

2. C++ Program to Add Two 4x4 Matrices

Ans:

#include <iostream>
using namespace std;

int main() {
    int A[4][4], B[4][4], C[4][4];
    cout << "Enter elements of first 4x4 matrix:\n";
    for(int i = 0; i < 4; i++) {
        for(int j = 0; j < 4; j++) {
            cin >> A[i][j];

Postfix evaluation 

#include<stdio.H>
int stack[20];
int top = -1;

void push(int x)
{
    stack[++top] = x;
}

int pop()
{
    return stack[top--];
}

int main()
{
    char exp[20];
    char *e;
    int n1,n2,n3,num;
    printf("Enter the expression :: ");
    scanf("%s",exp);
    e = exp;
    while(*e != '\0')
    {
        if(isdigit(*e))
        {
            num = *e - 48;
            push(num);
        }
        else
        {
            n1 = pop();
            n2 = pop();
            switch(*e)
            {
            case '+':
            {
                n3 = n1 + n2;
                break;
            }
            case '-':
            {
 ...

-Measure & Metric & Indicator

not provide enough information 

comparison of two or more measures

Compares a metric against a baseline

-To improve a process

Measure specific attributes 

of process

Develop meaningful metrics 

metrics provide indicators

Example Metrics derived:

Errors before software release, 

defects delivered to & 

reported by end-user

work products delivered

Human efforts expended

Calendar time expended

-Improving Software Quality 

& Organizational Performance

people.Product,technology

-Software measurement 

Direct Measures:Cost and effort

Line of Code & Execution Speed

Indirect Measures

Functionality,Quality

Complexity,Efficiency

Reliability,Maintainability

-1som:Derived by normalizing quality

LOC,cost,errors,defects

Effort...